import math

x1,y1,x2,y2 = (float(x) for x in input().split())
print(round(math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2), 8)) import math math float(x) for x in input().split() for x in input().split() x input().split() ().split () input split for x in input().split() float(x) float x x1,y1,x2,y2 = (float(x) for x in input().split()) x1 (float(x) for x in input().split()) y1 x2 y2 print(round(math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2), 8)) print round(math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2), 8) round math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2) math.sqrt math sqrt (x2 - x1) ** 2 + (y2 - y1) ** 2 (x2 - x1) ** 2 x2 - x1 x2 x1 2 (y2 - y1) ** 2 y2 - y1 y2 y1 2 8 y1,x2,y2 = (float(x) for x in input().split()) (float(x) for x in input().split()) y1 x1,y1,x2,y2 = (float(x) for x in input().split()) (float(x) for x in input().split()) x1 x2,y2 = (float(x) for x in input().split()) (float(x) for x in input().split()) x2 y2 = (float(x) for x in input().split()) (float(x) for x in input().split()) y2
import math

x1,y1,x2,y2 = (float(x) for x in input().split())
print(round(math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2), 8))
